I would speculate that the OP means UA only thinks flying to and from SFO and LAX to the east coast represents a transcontinental flight. And that UA doesn't think there are any other cities on the west coast worthy of getting the transcontinental label despite the geographical reality that EWR is on one side of the continental US and these cities are on the other side. As such those other west coast cities get a lower level of service (which I'm still curious what that means).